Question

One of the most fascinating phenomena in psychology is dissociative identity disorder (once known as “multiple personality disorder”). According to some psychologists, some people possess several distinct personalities, each of which is as rich and elaborate as the single personality that you yourself possess. As an example, at different times, a person with dissociative identity disorder might possess (a) a friendly, easygoing, and confident personality; (b) a shy, self-critical, and withdrawn personality; and (c) a grandiose, self-absorbed, manipulative personality. According to some psychologists, the different personalities of people with dissociative identity disorder may differ dramatically in their skill at particular tasks, their intelligence, or even their biological reactions to different allergens! To provide some empirical evidence for the existence of dissociative identity disorder, one psychologist repeatedly gave a standard intelligence test to a patient believed to be suffering from this problem. In particular, the psychologist asked a colleague who was blind to his hypothesis to administer the revised version of the Wechsler Adult Intelligence Scale (the WAIS-R) to one of his clients on four different occasions. This particular client, whom we will call Cari, appeared to have 11 distinct personalities, and each time she took the test she identified herself as a different person.

The first personality to take the test was “Wanda,” who received a score of 114 (somewhat above average) on the WAIS-R. A week later, “Melanie” took the same test and received a score of 123 (clearly above average). The third week, “Jasmine” received a score of 140 (approaching the genius range). Finally, on the fourth week, “Bassandra” received a high but not amazing score of 131. The psychologist who had been treating Cari concluded that each of Cari’s personalities has a different IQ and that this finding supports the validity of dissociative identity disorder. Although there now appears to be some evidence for the existence of dissociative identity disorder, we would not place the evidence about Cari in that category.

1.Critique this researcher’s conclusion – what flaws in methodology are present?

2.Can you suggest some things the researcher could do to improve upon the design of his study?

Answer 1

Answer.

Answer.1. The researcher’s claim to evidence in favour of Identification of dissociative identity disorder in the client presents a highly problematic research conclusion with an invalid result. The study can be criticised in terms of the methodological error of correlating personality with intelligence. It assumes that personality traits and a personality disorder like DID are the same as intelligence and the IQ test scores on Weschler’s Adult Intelligence Scale can have a high predictive validity for the underlying disorder. However, it is a theoretically established fact that personality an intelligence are two independent constructs and this makes the conclusions of the study highly doubtful. While the different alters or identities of the case may show different intelligence levels and skills, it does not imply that the finding of a difference in the IQ scores on repeated test phases can predict the existence of dissociative identity disorder.